The present invention relates to electrical cable and particularly to ribbon cables in which insulated conductors are juxtaposed, in a fixed relationship to each other, and more particularly, to transposed ribbon cables in which the conductors are in the shape of juxtaposed laterally flattened helices, methods and apparatus for manufacturing the same, and electromagnetic devices having ribbon cable as its magnetic windings.
Electrical cables in a variety of configurations have been available for an extended period of time. One of those varieties is ribbon cable. In ribbon cable, a plurality of conductors are disposed side by side to yield a cable with a roughly rectangular cross section as opposed to the round cross section of ordinary cables. The rectangular cross section permits use of the ribbon cable in applications where one or two dimensions are constrained.
Ribbon cables also provide improved field or armature and stator windings in a number of electromagnetic devices such as motors and generators and transformers. Ribbon cables in many applications provide for increased ease of assembly and improved efficiency. In some electromagnetic devices, eddy current losses can be reduced drastically by use of transposed ribbon cable. In other electromagnetic device, these eddy current losses can be balanced against other losses to produce an electromagnetic device having a greatly improved efficiency.
In transformer design, greater energy efficiency is achieved by using ribbon cable. Load losses can be reduced by using transposed ribbon cable. Similar benefits and similar energy efficiencies can be achieved in rotating electromechanical device design using ribbon cables and transposed ribbon cables.
Further, transposed cables heretofore have been limited as to the number of conductors in the cable. This limitation is the result of conventional methods and apparatus for manufacturing transposed cable. No such limitation exists for the ribbon cable of the invention.
It is therefore highly desirable to provide an improved ribbon cable, an improved ribbon cable that has a flattened generally rectangular cross section, an improved ribbon cable in which insulated conductors are juxtaposed in fixed relation to each other, an improved ribbon cable in which the conductors are at an angle to the longest dimension of the wire cable, an improved transposed ribbon cable, improved methods and apparatus for producing such cables, and an improved electromagnetic device using the ribbon cable of the invention as its magnetic windings.